Puerto Rican Syndrome, also known as Ataque de Nervios, is a culturally-bound syndrome exclusive to Latino cultures, mostly associated with Spanish-speaking people from the Caribbean, although commonly identified among all Iberian-descended cultures. It is a psychological syndrome that appears in Appendix I of the revised fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) as a culture-bound syndrome. The condition is characterized by a specific pattern of symptoms, including uncontrollable screaming or shouting, crying, trembling, sensations of heat rising in the chest and head, dissociative experiences, and verbal or physical aggression. The reaction is usually associated with a stressful event relating to the family, although it is not specifically defined as arising from such occurrences. Despite comparisons to panic attacks, investigators have identified Ataque de Nervios as a separate syndrome with measured differences in anxiety sensitivity and types of attacks. The phenomenon was first noted by U.S. Army medical officers in the 1950s, who labeled it as a disorder. The Puerto Rican Syndrome is a psychiatric disorder "founded" by U.S. Army medical doctors in the 1950s, who were attempting to understand the symptoms seen in Puerto Rican soldiers returning from the Korean War.